Hybrid vehicles and electric vehicles may be powered or partially powered via a battery pack. The battery pack may be comprised of a plurality of battery cells that are in serial and/or parallel electrical communication with each other. The battery pack may operate most efficiently and/or provide a longer life cycle when it is within a predetermined temperature range. If a temperature of the battery pack is greater than the predetermined temperature range, the battery pack may degrade. On the other hand, if a temperature of the battery pack is less than the predetermined temperature range, battery pack output capacity may degrade as the battery's internal resistance increases. Further, when a battery operates a cold temperatures, its life cycle may be reduced due to irreversible chemical reactions that may occur inside battery cells. Therefore, it may be desirable to have a high degree of confidence in the battery's actual temperature.
One way to determine temperature of a battery pack is to install one or more temperature sensors within the battery pack. However, temperature sensors and temperature sensor wiring may degrade over time. One mode of battery temperature sensor degradation may be to indicate battery pack temperature is within a desired battery pack operating range while actual battery pack temperature is higher or lower than the desired battery pack operating temperature range. If the battery pack is at a temperature that is out of a desired battery pack operating range and the battery pack temperature sensor indicates that battery pack temperature is with the desired battery pack operating temperature range, it may be possible to demand more output from the battery pack than is desired based on battery pack temperature sensor output. Consequently, battery pack operation may degrade.
The inventors herein have developed a system for operating a battery pack of a vehicle, comprising: a battery pack including a temperature sensor; and a controller including non-transitory instructions for adjusting battery pack output power in response to a comparison of an estimated battery pack temperature and a battery pack temperature determined via the temperature sensor.
By comparing output of a battery pack temperature sensor to an estimated battery pack temperature, it may be possible to provide the technical result of limiting battery pack output power when a battery pack temperature sensor is in a degraded condition. In particular, if more than a predetermined temperature difference exists between a battery pack temperature based on temperature sensor output and an estimated battery pack temperature, battery pack output may be limited so as to reduce the possibility of battery pack degradation.
The present description may provide several advantages. In particular, the approach provides for a way to reduce the possibility of demanding more than a desired amount of current from a battery pack. Further, the approach may be performed without redundant temperature sensors. Additionally, the approach may reduce the possibility of battery pack degradation.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.